737
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
34 SFC Program and Step Ladder
34.1 SFC Program
31
FN
C
275-FN
C
279
Da
ta
Tr
ans
fe
r 3
32
FN
C
280
-F
N
C
28
9
H
igh Speed
Pr
oces
si
ng 2
33
FN
C
290-FN
C
299
Ext
ensi
on Fi
le
R
egi
st
er
34
SF
C
•S
T
L
Pr
o
g
ra
m
m
in
g
35
In
te
rru
p
t
Funct
ion
36
Sp
e
cia
l De
vic
e
37
E
rro
r C
o
d
e
A
V
e
rs
ion U
p
In
fo
rm
a
tio
n
B
Ex
ec
ut
ion Ti
m
e
s
C
Appl
ic
ab
le
In
st
ru
ct
ion Li
st
4. Inputting and indicating a program using GX Developer
• Input a circuit for setting the initial state relay to ON using the relay ladder.
In this example, the initial state relay S0 is set to ON in a ladder block using the special auxiliary relay
M8002 which turns ON instantaneously when the PLC mode is changed from STOP to RUN.
• When inputting a program using GX Developer, write a relay ladder program to a ladder block, and write an
SFC program to an SFC block.
• Programs expressing operations in state relays and transfer conditions are handled as internal circuits of
the state relays and transfer conditions.
Create each one using a relay ladder.
For the details of programming procedure in GX Developer, refer to GX Developer Operating Manual.
Y023
Y021
Write a circuit not
belonging to SFC to a
ladder block using a
relay ladder.
Write an SFC program
to an SFC block.
Ladder block
SFC block
M8002
SET
S0
Program for setting the initial state
relay to ON
Indicate the state relay number and
transfer condition number.
0
20
0
1
21
2
22
3
23
4
24
5
S0
RET
END
X000
TRAN
Y021
Y023
X001
TRAN
T0
X002
TRAN
Y023
Y021
T0
TRAN
Y021
Y023
X003
TRAN
X002
TRAN
When a program is input using GX Developer,
“RET” and “END” are automatically written.
K50
Input them as
internal circuits.